JP2017152696A - Flexible wiring board or flexible conductor structure, manufacturing method for the same, and electronic element including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible wiring board or a flexible conductor structure with the excellent electric physical property and high elasticity, a manufacturing method for the same, and an electronic element including the same.SOLUTION: The flexible wiring board includes a first resin layer and a conductive layer disposed on one surface of the first resin layer. The conductive layer contains conductive metal and a nanocarbon material dispersed in the conductive metal, and includes a bendable part in at least one part of the conductive layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a flexible wiring board or a flexible conductor structure, a manufacturing method thereof, and an electronic device including the same.

  A flexible conductor structure such as a flexible wiring board or a flexible transparent electrode is used in various electronic devices. Due to the reduced size, improved functionality, and wearable tendency of these devices, flexible wiring boards or flexible conductor structures have a high level of conductivity and bend resistance that can withstand harsh and diverse bend deformations. It has been demanded. For example, a wiring board or conductor structure maintains its original electrical properties (for example, low electrical resistance) even when placed under repeated folding or bending with a small radius of curvature. There is a need.

  Attempts have been made to provide flexible wiring boards or flexible conductor structures using metal wiring such as copper, metal nanowires, metal oxides, and graphene. It has been difficult to satisfy both excellent electrical properties and high bending resistance. Therefore, it is necessary to develop a wiring board or a flexible conductor structure that can realize desired mechanical properties such as high bending resistance as well as excellent electrical properties.

  On the other hand, the transparent electrode for a touch panel has been required to have high transparency instead of requiring electrical conductivity as much as the field of flexible printed wiring boards. Conventionally, indium tin oxide (ITO) has been used for a transparent electrode for a touch panel, but from the viewpoint of improving conductivity and bending resistance, development of an alternative material is necessary. For this, methods using metal meshes such as copper and silver, nanowires such as copper and silver, and transparent conductive polymers have been proposed. In recent years, both high conductivity and high flexibility have been demanded in both flexible printed wiring boards and transparent electrodes for touch panels.

JP 2008-177165 A

  One embodiment relates to a flexible wiring board having excellent electrical properties and high bending resistance.

  Another embodiment relates to a method of manufacturing the flexible wiring board.

  Another embodiment relates to an electronic device including the flexible wiring board.

  Other embodiments relate to flexible conductor structures.

  According to one embodiment, a flexible wiring board includes a first resin layer and an electrically conductive layer disposed on one surface of the first resin layer. The conductive layer includes an electrically conductive metal and a nanocarbon material dispersed in the conductive metal, and is used with a bending portion in at least one portion of the conductive layer. .

  In a preferred embodiment, a second resin layer is disposed on the conductive layer.

  In a preferred embodiment, the first resin layer and the second resin layer are electrically insulative.

  In a preferred embodiment, the first resin layer and the second resin layer are formed of a polyester resin, a polyacrylic resin, a polyolefin resin, a cellulose resin, a polycarbonate resin, a polyimide resin, a polyamide resin, or a polyphenylene sulfide. , Polyether ether ketone, liquid crystal polymer, epoxy resin, or combinations thereof.

  In a preferred embodiment, the conductive metal is silver (Ag), copper (Cu), nickel (Ni), gold (Au), aluminum (Al), tungsten (W), platinum (Pt), iron (Fe). Or a combination thereof.

  In a preferred embodiment, the conductive metal includes silver, copper, or a combination thereof.

  In a preferred embodiment, the conductive layer is a rolled product of a co-deposited composite obtained by electrodeposition of the conductive metal and the nanocarbon material.

  In a preferred embodiment, the rolled product is rolled so that the eutectoid composite obtained by electrodeposition is 50% or less of the thickness obtained by the electrodeposition.

  In a preferred embodiment, the nanocarbon material includes carbon nanotubes, fullerene, graphene, or a combination thereof.

  In a preferred embodiment, at least a part of the nanocarbon material is oriented parallel to the surface of the first resin layer.

  In a preferred embodiment, the number of nanocarbon materials oriented parallel to the surface of the first resin layer is greater than the number of nanocarbon materials oriented perpendicular to the surface of the first resin layer.

  In a preferred embodiment, the content of the nanocarbon material is 0.01% by weight or more based on the total weight of the conductive layer.

  In a preferred embodiment, the content of the nanocarbon material is 0.05% by weight or more and 1% by weight or less based on the total weight of the conductive layer.

  A bending rate radius of the bent portion may be 3 mm or less.

  The bent portion may be formed by a repetitive operation of sliding bending, folding bending, hinge bending, or a combination thereof.

  In a preferred embodiment, when a flexibility test is performed in which the wiring board is bent by 40,000 diffractions with a bending rate radius (bending radius) of 1 mm, the resistance change rate is 400% or less.

  In a preferred embodiment, the conductive layer has a thickness of 0.2 μm to 20 μm.

  In a preferred embodiment, the first resin layer has a thickness of 10 μm to 150 μm.

  In another embodiment, an electronic device including the flexible wiring board described above is provided.

  The electronic element may be a display, a touch panel screen, a wearable device, a battery, a stretchable organic light emitting diode display, a stretchable human body motion sensor, a stretchable artificial muscle, a stretchable actuator, or a stretchable semiconductor.

  In addition, the method for manufacturing the flexible wiring board provided by another embodiment includes a step of preparing a plating bath containing a conductive metal salt compound and a nanocarbon material (for example, a plurality of carbon nanotubes). Disposing a metal plate and a counter electrode in the plating bath, and conducting electrodeposition by passing a current between the metal plate and the counter electrode, and the conductive metal and the conductive metal on the metal plate Forming a eutectoid composite containing the nanocarbon material dispersed in the electrodeposite and the eutectoid composite obtained by the electrodeposition has a thickness of 50% or less of the thickness obtained by the electrodeposition Rolling, and disposing a first resin layer on one surface of the rolled eutectoid composite.

  In a preferred embodiment, the rolling increases the number of nanocarbon materials oriented parallel to the surface of the first resin layer.

  In another embodiment, the flexible conductor structure includes a substrate and a conductive layer disposed on one surface of the substrate, the conductive layer including a conductive metal and the conductive layer. A nanocarbon material (for example, a plurality of carbon nanotubes) dispersed in a conductive metal is included, and the flexible conductor structure is used with a bent portion in at least one portion of the conductive layer.

  In a preferred embodiment, an additional resin layer is disposed on the conductive layer.

  In a preferred embodiment, the conductive layer includes a rolled product of a eutectoid composite by electrodeposition of the conductive metal and the nanocarbon material.

  In a preferred embodiment, the flexible conductor structure is configured such that the number of nanocarbon materials oriented parallel to the surface of the substrate is equal to the number of nanocarbon materials oriented perpendicular to the surface of the substrate. is more than.

  In a preferred embodiment, the conductive layer is patterned to have an open space.

  In a preferred embodiment, when a flexibility test is performed in which the structure is bent 40,000 times with a bending radius of 1 mm, the resistance change rate is 400% or less.

  In a preferred embodiment, the structure is a flexible wiring board, a transparent electrode, or a lead wire.

  According to the present invention, a flexible wiring board or flexible conductor structure having excellent electrical properties and high bending resistance, a manufacturing method thereof, and an electronic device including the same are provided.

1 schematically shows a cross section of a flexible wiring board according to an embodiment. 1 is a schematic exploded view of an electronic device including a flexible wiring board or a flexible conductor structure according to an embodiment. FIG. It is a typical cross section of the plating apparatus of flexible wiring board manufacture in an Example. It is a simple flowchart of the process of manufacturing the wiring board in an Example. 4 is an SEM image of a flexible wiring board observed from the conductive layer side in the flexible wiring board having a first resin layer and a conductive layer having a mesh pattern manufactured in Example 1. FIG. In the flexible wiring board including the first resin layer manufactured in Example 1, the conductive layer having the mesh pattern, and the second resin layer, the schematic view of the substrate observed from the second resin layer side, and the side view. It is a schematic diagram of a substrate. 5 is an SEM image observed from the conductive layer side in the flexible wiring board including the first resin layer manufactured in Comparative Example 1 and a conductive layer having a mesh pattern. It is the schematic of the experimental apparatus of the flexibility test in Experimental example 2. FIG. 6 is a graph showing the results of a flexibility test of Experimental Example 2. In the flexibility test of the rolled copper wiring board of the comparative example 2, the resistance change rate of a test piece is graphed. In the flexibility test of the aluminum wiring board of the comparative example 3, the resistance change rate of a test piece is graphed. The life of a flexibility test performed using a wiring board having a conductive layer containing silver and carbon nanotubes having a thickness of 6 μm was set to 6200 times (the life was calculated by linear approximation from the results of 5000 times and 10,000 times). It is a figure which shows the relationship between the thickness of the conductive layer containing the calculated silver and carbon nanotube, and the lifetime of a flexibility test.

  Advantages and features of the technology of the present invention described below, and methods for achieving them will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention can be implemented in a variety of different forms and is not limited to the embodiments described herein. Unless otherwise explained, all terms used in this specification (including technical and scientific terms) can be used as meanings commonly understood by those having ordinary knowledge in the technical field. Also, terms defined in commonly used dictionaries are not ideally or excessively interpreted unless clearly defined. If a component that is a part of the entire specification is “included”, it means that it can further include other components rather than excluding other components unless otherwise stated to the contrary. Means that. The singular forms also include the plural unless specifically stated in the text.

  Hereinafter, embodiments of the present invention will be described in detail.

  According to an embodiment of the present invention, a flexible wiring board having a first resin layer and a conductive layer disposed on one surface of the first resin layer, the conductive layer being a conductive metal. And a flexible wiring board (hereinafter, also simply referred to as “wiring board”) including a nanocarbon material dispersed in the conductive metal. In addition, the flexible wiring board is used with a bending portion in at least one portion of the conductive layer.

  According to another embodiment of the present invention, there is provided a flexible conductor structure having a base material and a conductive layer disposed on one surface of the base material, wherein the conductive layer is a conductive metal. And a flexible conductor structure (hereinafter also simply referred to as “conductor structure”) including a plurality of carbon nanotubes dispersed in the conductive metal. Also, the flexible conductor structure is used with a bending portion in at least one portion of the conductive layer.

  A flexible wiring board or flexible conductor structure according to an embodiment of the present invention can exhibit a high bending resistance even under a small bending rate radius and / or repeated bending conditions, and thus display, wearable It can be used for various bent portions of various electronic elements such as devices.

  Although it does not restrict | limit especially as a mechanism in which the flexible wiring board or flexible conductor structure of this invention shows the above high bending resistances, It is considered as follows. That is, the flexible wiring board or flexible conductor structure of the present invention includes a conductive metal and a nanocarbon material (or a plurality of carbon nanotubes) dispersed in the conductive metal. As described above, it is speculated that the nanocarbon material (or a plurality of carbon nanotubes) is dispersed in the conductive metal, so that the carbon nanotube suppresses the occurrence of metal cracks, thereby improving the bending resistance. The In particular, in a preferred embodiment of the present invention, a plurality of carbon nanotubes contained in the conductive layer are oriented in parallel with the first resin layer. In this form, cracks are generated in the form of cutting the carbon nanotubes. Therefore, the crack is suppressed and the bending resistance is further improved.

  A flexible wiring board 100 according to an embodiment of the present invention includes a first resin layer 10 and a conductive layer 20 disposed on one surface of the first resin layer. The second resin layer 30 may be disposed on the conductive layer 20 as, for example, a coverlay film (see: FIG. 1). That is, the flexible wiring board in one embodiment of the present invention further includes a second resin layer on the conductive layer.

  In a preferred embodiment, the first resin layer and the second resin layer are electrically insulating. For example, the first resin layer and the second resin layer are not limited to this, but are preferably polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyacrylic resins such as polymethyl (meth) acrylate, polyethylene, polypropylene, and the like. A polyolefin resin, a cellulose resin such as triacetyl cellulose, a polycarbonate resin, a polyimide resin, a polyamide resin, polyphenylene sulfide, a polyether ether ketone, a liquid crystal polymer, an epoxy resin, or a combination thereof is included.

  In a preferred embodiment, the first resin layer is polyimide. The first resin layer may be optically transparent. The first resin layer may contain a low elastic resin. The second resin layer is preferably polyimide. The second resin layer may be optically transparent. The first resin layer may have an elastic modulus of 3.0 GPa or less (for example, 0.1 GPa to 3 GPa, 0.2 GPa to 1 GPa, 0.3 GPa to 1 GPa), and Tg of 250 ° C. or higher (for example, 275 ° C. or higher). 300 ° C. or more and 400 ° C. or less, 375 ° C. or less, or 350 ° C. or less), and the elongation at break may be 8% or more, 15% or more, or 20% or more. The elongation at break may be 100% or less, 90% or less, or 80% or less, but is not limited thereto. These polymers may be synthesized by a known method or may be obtained commercially.

  The thickness of the first resin layer is not particularly limited and may be appropriately selected. For example, the thickness of the first resin layer is not limited to this, but is preferably 10 μm or more, more preferably 10 μm to 150 μm (for example, 15 μm or more or 20 μm or more, and 300 μm or less, 190 μm or less, or 180 μm or less). . A configuration example of an actual display (OLED) is shown in FIG. However, the flexible wiring board (FPC) is often bent and placed under the display. A TFT electrode exists in the display, and a flexible wiring substrate or a conductive structure (for example, an electrode) according to an embodiment of the present invention can be used for the wiring.

  The flexible wiring board or the conductive structure according to the embodiment of the present invention can be used for a touch sensor of a transparent electrode (TSP) or can be used for a lead wire (end wiring) of the transparent electrode. As described above, since the touch sensor and the FPC are often arranged outside the thick display, the strain (ε) may be 0.03 or more, that is, 3% or more. When the strain (ε) is 0.01 or more, the conventional Cu or Al wiring has insufficient bending resistance, and the resistance value tends to increase. The flexible wiring board or conductive structure according to an embodiment of the present invention is slightly more effective than the prior art when the strain is used at 0.01 or more, and the strain is used at 0.03 or more. If it is more effective. Note that the total thickness of the display shown in FIG. 2 exceeds 200 μm. In that case, the wiring in the vicinity of the bending center is hardly strained, but the strain is often 0.03 or more at a location 100 μm away from the bending center. Since the flexible wiring board or the conductive structure according to the embodiment of the present invention can be disposed at a location where the strain is large, the degree of freedom in design is increased.

  An adhesive layer (not shown) may be interposed between the first resin layer and the conductive layer, but is not limited thereto. The first resin layer may be formed of a single resin or a mixture of a plurality of different resins. The first resin layer can be produced by bonding two or more identical or different polymer films to each other under, for example, heating and / or pressing conditions.

  The conductive layer contains a conductive metal and a nanocarbon material (preferably a plurality of carbon nanotubes). The nanocarbon material (preferably a plurality of carbon nanotubes) is dispersed in the conductive metal. That is, the nanocarbon material (preferably a plurality of carbon nanotubes) can be dispersed, for example, uniformly or non-uniformly within a conductive metal matrix to form a composite. Here, the composite in which the nanocarbon material is dispersed in the matrix of the conductive metal is preferably a metal in the plating bath using a plating bath containing the conductive metal and the nanocarbon material, as will be described later. This is a eutectoid composite comprising a conductive metal and a nanocarbon material obtained by placing a plate and a counter electrode, and performing electrodeposition by flowing a current between the metal plate and the counter electrode. More preferably, it is a rolled product obtained by rolling the eutectoid composite obtained by electrodeposition so as to have a thickness of 50% or less of the thickness obtained by electrodeposition. Accordingly, the conductive layer preferably contains a eutectoid composite formed by electrodeposition of a conductive metal and a nanocarbon material, more preferably a eutectoid composite formed by electrodeposition of a conductive metal and a nanocarbon material. Contains a rolled product (rolled eutectoid composite) obtained by rolling the body. In other words, the conductive layer is a rolled product of a eutectoid composite by electrodeposition of a conductive metal and a nanocarbon material (preferably carbon nanotubes).

  The conductive metal is preferably silver (Ag), copper (Cu), nickel (Ni), gold (Au), aluminum (Al), tungsten (W), platinum (Pt), iron (Fe) or a combination thereof including. The conductive metal can be selected in consideration of cost, circuit formability, bending resistance, corrosion resistance, and the like. In one embodiment, the conductive metal more preferably contains silver (Ag) and / or copper as the main component, or may be composed of silver (Ag) or copper. According to one embodiment, the conductive layer containing silver (Ag) can also suppress the ion migration phenomenon.

  Nanocarbon materials are effective in reducing metal corrosion by being composited with metal. Therefore, corrosion of easily corroded metals such as copper, silver, and aluminum can be suppressed, and an increase in Young's modulus (extension elastic modulus) due to corrosion can be suppressed, so that flexibility of the metal is maintained and flex resistance is improved. Further, since the corrosion is suppressed, an increase in surface resistance can be prevented.

  Among these, carbon nanotubes are highly effective because they maintain electrical conductivity even when the metal is broken during bending.

  The nanocarbon material preferably comprises carbon nanotubes, fullerenes, graphene, or combinations thereof. In a more preferred embodiment of the flexible wiring board of the present invention, the nanocarbon material includes a plurality of carbon nanotubes.

  Here, the carbon nanotube is a carbon allotrope having a nanostructure (for example, a cylindrical nanostructure), and includes carbon nanoparticle, carbon nanorope, carbon nanoribbon, carbon nanofibril, carbon nanoneedle, carbon nanorod. Carbon nanocones and the like may also be included. The carbon nanotubes may include, but are not limited to, single wall carbon nanotubes (SWCNT), double wall carbon nanotubes (DWCNT), multi-wall carbon nanotubes (MWCNT), or combinations thereof. In the case of a single-wall carbon nanotube, the electrical conductivity of the wiring board can be further improved. In the case of double-walled carbon nanotubes or multi-walled carbon nanotubes, the manufacturing cost of the wiring board can be reduced.

  The size of the nanocarbon material (for example, carbon nanotube) is not particularly limited, and can be appropriately selected. For example, the size (diameter) of the carbon nanotube is not limited to this, but is preferably 200 nm or less, more preferably 50 nm or less, still more preferably 40 nm or less, even more preferably 30 nm or less, and most preferably 20 nm or less. is there. The size of the carbon nanotube is preferably 0.4 nm or more. A diameter in this range is advantageous from the viewpoint of dispersibility of the nanocarbon material (carbon nanotube). Since the thickness of the carbon nanotube in the range of 0.4 nm or more and 50 nm or less is smaller than the space of the wiring, any of them can be used. In the case of fullerene, the electron particle diameter is about 7.1 mm. As the number of carbon atoms increases to 60, 70, 74, 76, and 78, any of them can be used. Graphene is a planar material, but is desirably used in the form of small pieces of 100 nm or less.

  The length of carbon nanotubes (or the size in the lateral direction of graphene) is not particularly limited, and an appropriate one may be selected. The length of the carbon nanotube is not limited to this, but is preferably 100 nm or more, more preferably 1 μm or more, still more preferably 2 μm or more, and even more preferably 3 μm or more. The length of the carbon nanotube is not limited to this, but is preferably 100 μm or less, and more preferably 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. When the conductive layer forms fine wiring, it is preferable to use carbon nanotubes that are shorter than the space of the wiring (that is, the width of the conductive layer). Specifically, if the wiring space is 3 μm, the risk of wiring failure is reduced by using a nanocarbon material (for example, carbon nanotube or graphene) having a size (for example, length or lateral size) of less than 3 μm. can do.

  Nanocarbon materials can be synthesized or commercially obtained by known methods. For example, the carbon nanotubes may be obtained commercially, or any known method (for example, vapor deposition methods such as chemical vapor deposition, catalytic chemical vapor deposition, carbon catalytic vapor deposition, etc. , High pressure carbon monoxide process, arc discharge, laser application method, plasma synthesis method, etc.).

  Fullerenes and graphenes can also be synthesized or marketed by known methods.

  The content of the nanocarbon material (for example, carbon nanotube) is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, still more preferably 0.00% by weight, based on the total weight of the conductive layer. It is 06% by weight or more, and more preferably 0.09% by weight or more. There is no particular upper limit on the carbon nanotube content, but if the carbon nanotube content is excessively high, plating becomes difficult. Considering the actual situation, the upper limit of the carbon nanotube content is not particularly limited, but is preferably 3% by weight or less (or 2.5% by weight or less or 2% by weight or less), more preferably 1% by weight or less. Conceivable.

  The conductive layer is obtained by electrodepositing (for example, electroplating) to obtain a eutectoid complex of a conductive metal and a nanocarbon material (for example, carbon nanotube), and rolling the obtained eutectoid complex (for example, hot Or cold rolling). A specific method for manufacturing the eutectoid composite and a method for rolling the eutectoid composite will be described in detail in the method for manufacturing a wiring board.

  In the eutectoid composite, the nanocarbon material (for example, a plurality of carbon nanotubes) is uniformly dispersed in the conductive metal matrix, and at least a part of them is formed on the surface of the first resin layer (by the rolling process). Can be oriented parallel to one surface. That is, preferably at least a part of the plurality of carbon nanotubes is oriented parallel to the surface of the first resin layer. In one embodiment, preferably, the number of carbon nanotubes oriented parallel to the surface of the first resin layer is greater than the number of carbon nanotubes oriented perpendicular to the surface of the first resin layer.

  Similarly, in the conductor structure, the conductive layer includes a conductive metal and a plurality of carbon nanotubes dispersed in the conductive metal. At this time, similarly to the conductive layer in the wiring board, a eutectoid complex of conductive metal and carbon nanotubes is obtained from electrodeposition (for example, electroplating), and the obtained eutectoid complex is rolled (for example, heat Or cold rolling). In the eutectoid composite, the plurality of carbon nanotubes are uniformly dispersed in the conductive metal matrix, and at least a part of them can be oriented parallel to the surface (one surface) of the substrate by rolling. That is, preferably at least a part of the plurality of carbon nanotubes is oriented parallel to the surface of the substrate. In one embodiment, preferably the number of carbon nanotubes oriented parallel to the surface of the substrate is greater than the number of carbon nanotubes oriented perpendicular to the surface of the substrate.

  Without being bound by any particular theory, the rolling process allows at least a portion of the carbon nanotubes to be oriented in a predetermined direction, without substantial changes to the electrical properties of the conductor, It seems that the bending resistance of the conductor structure can be improved. The orientation of the carbon nanotubes in the conductive layer can be obtained by confirming a scanning electron microscope (SEM) image or a transmission electron microscope (TEM) image of the wiring cross section. Here, “parallel to the surface of the first resin layer” or “parallel to the surface of the base material” is based on a straight line obtained by extending the axis in the length direction of the carbon nanotube. An angle that does not contact or intersects the surface of the layer (first resin layer or substrate) (an angle that intersects with an acute angle among the intersecting angles) is 75 degrees or less, for example, 70 degrees or less, 65 degrees or less, 60 It may mean less than, 55 degrees, less than 50 degrees, or less than 45 degrees.

  The rolled product is preferably obtained by rolling so that the eutectoid composite obtained by electrodeposition is 50% or less of the thickness obtained by electrodeposition. In a more preferred embodiment, the rolled product is preferably 45% or less, more preferably 40% or less, still more preferably 35% or less, even more preferably 30% or less, most preferably the thickness obtained by electrodeposition. Rolled to 25% or less. The limit of rollability is determined by the spreadability of the metal. There is no problem as long as pinholes do not occur. The thickness ratio can be appropriately selected in consideration of the cost and the dispersibility of the nanocarbon material (for example, carbon nanotube). Rolling at such a thickness ratio is advantageous in terms of the dispersibility of the nanocarbon material (for example, carbon nanotubes) and the orientation in the lateral direction. That is, when the eutectoid composite is rolled within the above range, the number of carbon nanotubes oriented in parallel with the first resin layer can be increased, which leads to improvement in bending resistance.

  The preferable form regarding the orientation and rolling of the carbon nanotube in the conductive layer in the wiring substrate is the same for the conductor structure.

  The thickness of the conductive layer varies greatly depending on the use site of the wiring board (or conductor structure). For example, when used for a flexible wiring board, the thickness of the conductive layer is preferably in the range of 0.1 μm to 30 μm, more preferably in the range of 0.2 μm to 20 μm, further preferably in the range of 2 μm to 15 μm, and in the range of 4 μm to 10 μm. Is even more preferred. The flexible wiring board needs to have a thicker conductor in order to prevent electric signals from being attenuated.

  On the other hand, in the case of a conductor structure (when used for a touch panel electrode or lead wire), the thickness of the conductive layer can be reduced. The thickness of the conductive layer is preferably in the range of 0.1 μm to 2 μm, more preferably in the range of 0.2 μm to 1 μm.

  As will be described later, the bending resistance becomes better as the conductive layer becomes thinner. In the present invention, the bending resistance can be improved even when a relatively thick conductive layer is included.

  When a wiring board (or a conductor structure to be described later) is used in various electronic devices, it is configured to have a bent portion at least at a part of the conductive layer. For example, when a wiring board or conductor structure is included and used in various electronic devices such as flexible displays, folder type smartphones, E-paper, etc., it may be bent or twisted by the operation of the device on which it is mounted. Or deformed to provide a bend at any location in the conductive layer.

  For example, the bending rate radius (bending radius) of the bent portion of the wiring board (or conductor structure) is preferably 3 mm or less, more preferably 2 mm or less, and even more preferably 1 mm or less. The bent portion may be formed by sliding bending, folding bending, hinge bending, or a combination thereof, or by repeated operations thereof.

  When the wiring board (or conductor structure) is bent 40,000 times with a bending rate radius of 1 mm, the resistance change rate defined by the following formula is preferably 400% or less.

[(R−R ₀ ) / R ₀ ] × 100
Here, R ₀ is an initial resistance, and R is a resistance after bending 40,000 times.

  For example, the resistance change rate is more preferably less than 100%, further preferably less than 40%, and even more preferably less than 10%. It should be noted that the degree of difficulty varies greatly depending on the strain (ε) of the metal even if it is simply a bendability test with a radius of 1 mm. In the metal strain, the bent portion is determined by the distance from the bent center line (Neutral Plane). In FIG. 8, the distance X (m) from the bending center line can be expressed by the following equation.

^{_{X = [t PI 2 E PI}} + {(t PI + t Me) 2 -t PI 2} E Me + {(t PI + t Me + t CL) 2 - (t PI + t Me) 2} E CL] / {2 _{(t PI E PI + t Me} E Me + t CL E CL)}
t _CL : thickness of cover layer (Cover Layer) (m)
t _Me : metal layer thickness (m)
_tPI : thickness of support layer (usually polyimide) (m)
E _CL : Young's modulus (Pa) of the cover layer (Cover Layer)
E _Me : Young's modulus of metal layer (Pa)
E _PI : Young's modulus (Pa) of the support layer (usually polyimide)
The strain ε at that time can be expressed by the following equation.

ε = X / (0.001−t _CL −t _Me −X)
Normally, when the strain is 0.01 or less, that is, when the metal is stretched by 1% or less, it is easy to bend 40,000 times with a bending rate radius (bending radius) of 1 mm, but when the strain is 0.03 or more. That is, when the metal stretches by 3% or more, it is very difficult to bend 40,000 times with a bending rate radius (bending radius) of 1 mm. However, the flexible wiring board or the conductor structure according to the embodiment enables bending with a bending rate radius (bending radius) of 1 mm even when the strain is relatively large as 0.03 or more.

  Another embodiment provides an electronic device that includes the flexible wiring board described above or the flexible conductor structure described below. The electronic element may be a display, a touch panel screen, a wearable device, a battery, a stretchable organic light emitting diode display, a stretchable human body motion sensor, a stretchable artificial muscle, a stretchable actuator, or a stretchable semiconductor.

  Referring to FIG. 2 as an example of a non-limiting electronic device, a flexible wiring board or flexible conductor structure according to an embodiment is a flexible printed circuit board (FPC) in the display device of FIG. Or a touch screen panel, a display wiring structure (not shown), a transparent electrode (not shown), or the like.

  Hereinafter, the method for manufacturing the flexible wiring board will be described in detail.

  The manufacturing method includes the steps of providing a plating bath including a conductive metal salt compound and a nanocarbon material (eg, a plurality of carbon nanotubes), and disposing a metal plate and a counter electrode in the plating bath. A current is passed between the metal plate and the counter electrode to perform electrodeposition (for example, electroless plating), and the conductive metal and the carbon nanotubes dispersed in the conductive metal are disposed on the metal plate. Forming a depositing composite, rolling the eutectoid composite obtained by electrodeposition so as to have a thickness of 50% or less of the thickness obtained by electrodeposition, and the rolling Disposing a resin layer on one surface of the eutectoid composite.

  In preparing the plating bath, the conductive metal salt compound may be a metal cyanide. For example, the metal cyanide may be silver cyanide, copper cyanide, nickel cyanide, gold cyanide, aluminum cyanide, or combinations thereof.

  The plating bath may include an alkali metal cyanide salt such as potassium cyanide and sodium cyanide, a conductive salt such as potassium carbonate, a brightener, a surfactant, and combinations thereof. The amounts of metal cyanide, alkali metal cyanide salt, conductive salt, brightener, and surfactant (ie, dispersant) can be adjusted appropriately and are not particularly limited. For example, the conductive salt may be used in an amount that can improve the conductivity of the plating bath. The surfactant is used to improve the dispersibility of the carbon nanotubes in the plating bath, and those known to ordinary engineers and / or commercially available products may be used. Examples of the surfactant include sodium dodecyl sulfate (SDS) and hydroxypropyl cellulose (HPC), but are not limited thereto.

The content of the dispersant may range from ^{0.1 × 10 -3 M~3 × 10 -3} M range or ^{0.5 × 10 -3 M~2 × 10 -3} M, but, in this Not limited. Such a range is advantageous in that the improved dispersibility of the carbon nanotubes can be secured without deteriorating the physical properties of the plated composite. The brightener is for smoothing the surface of the metal, and those known to ordinary engineers and / or commercially available products may be used.

  The nanocarbon material (for example, a plurality of carbon nanotubes) is as described above. The content of carbon nanotubes can be appropriately selected in consideration of the content of carbon nanotubes necessary for the conductive layer. For example, the carbon nanotube content is not particularly limited, but is preferably 1 gram or more, more preferably 2 grams or more, even more preferably 3 grams or more, and even more preferably 4 grams or more per liter of the plating bath. Further, in a more preferable form, for example, it is preferably 5 grams or more, 6 grams or more, 7 grams or more, 8 grams or more, or 10 grams or more in a preferable order (ascending order), but is not limited thereto. For dispersion of carbon nanotubes, methods such as stirring and ultrasonic dispersion may be used, but are not limited thereto.

  A metal plate (that is, a covering) and a counter electrode are arranged in the plating bath, and an electric current is passed (that is, a voltage is applied between the metal plate and the counter electrode) to perform electrodeposition. The types of the metal plate and the counter electrode are not particularly limited, and may be appropriately selected. The metal plate may include copper, but is not limited thereto. The metal plate may be cleaned before placement.

When a voltage is applied, the nanocarbon material (for example, a plurality of carbon nanotubes) and conductive metal ions in the plating bath move toward the metal plate, and co-deposit on the surface of the metal plate. As a result, a structure is obtained in which the eutectoid composite containing the conductive metal and the carbon nanotube dispersed in the conductive metal is arranged on the surface of the metal plate. When the voltage is applied, the carbon nanotubes can be prevented from being precipitated by stirring. The plating conditions are not particularly limited and can be appropriately selected. For example, the plating can proceed at a temperature of 10 ° C. to 30 ° C. at 0.5 to 4.0 A / dm ² , but is not limited thereto.

  The thickness of the eutectoid composite may be selected by adjusting the plating time and the like. For example, the thickness of the eutectoid composite is not limited to this, but is preferably 10 μm or more, more preferably 50 μm or more, and even more preferably 100 μm or more.

  The obtained eutectoid composite is subjected to a rolling treatment (for example, hot rolling and / or cold rolling) and rolled to 50% or less of the thickness of the eutectoid composite obtained by electrodeposition. Is preferred. For example, in a more preferred form, the rolling is preferably 45% or less, more preferably 40% or less, even more preferably 35% or less, even more preferably 30% of the thickness of the eutectoid composite obtained by electrodeposition. In the following, it is most preferable that the thickness is 25% or less. The number of carbon nanotubes oriented in parallel with the first resin layer can be increased by the rolling treatment within the range of the rolling rate, which leads to improvement in bending resistance. That is, the rolling preferably increases the number of nanocarbon materials oriented parallel to the surface of the first resin layer. Specifically, by rolling the eutectoid composite to a thickness of 50% or less, 80% or more of the carbon nanotubes contained in the conductive layer are parallel to the first resin layer. It seems to be oriented. The orientation is observed by SEM or TEM as described above. According to the study of the present inventor, even if the film is non-oriented before rolling, by carrying out the rolling so as to have a thickness of 50% or less, most (most) carbon materials are based on the first resin layer Oriented in parallel. The degree of orientation (inclination) varies depending on the rolling rate (for example, depending on the height of the rolling rate).

  The rolling process can be performed by passing a eutectoid complex (a structure including a eutectoid complex) between two or more rotating rollers. The hot rolling may be performed at a temperature higher than the recrystallization temperature of the metal, and the cold rolling may be performed at a temperature lower than the recrystallization temperature of the metal. After the rolling process, an annealing step may be performed depending on selection. Annealing can be performed at 60 ° C. to 350 ° C., or 100 ° C. to 250 ° C., but is not limited thereto.

  The rolling method may further include a step of removing the metal plate (that is, the covering) from the structure including the eutectoid composite before and after rolling, for example, by etching. Specific conditions for such etching are known.

  A resin layer (first resin layer) is laminated (laminated) on one surface of the rolled eutectoid composite obtained as described above, for example, by heating and / or pressing. The detailed contents for the resin layer are as described in the first resin layer.

  The rolled film (that is, the conductive layer) disposed on the first resin layer can be patterned by an appropriate patterning method (for example, a photolithography method) to form a wiring. The line width of the patterned wiring (or conductor) can be selected as appropriate. For example, 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, 10 μm or less, 9 μm or less, 8 μm or less, 7 μm or less, 6 μm or less, 5 μm or less, 4 μm or less, The thickness is preferably 3 μm or less, or 2 μm or less, but is not limited thereto. Further, the line (L) / space (S) ratio of the patterned wiring (or conductor) can be appropriately selected. The specific contents of the conductive layer pattern formation by photolithography are known.

  A second resin layer (for example, a cover lay) may be laminated on the patterned conductive layer. The detailed contents for the second resin layer are as described above.

  In another embodiment, the flexible conductor structure includes a substrate and a conductive layer disposed on one surface of the substrate, the conductive layer including a conductive metal and the conductive layer. A nanocarbon material (for example, a plurality of carbon nanotubes) dispersed in a conductive metal is included, and the flexible conductor structure is used with a bent portion in at least one portion of the conductive layer.

  An additional resin layer (for example, a cover lay) may be disposed on the conductive layer. The conductive layer preferably includes a rolled product of a eutectoid composite by electrodeposition of a conductive metal and a nanocarbon material (for example, carbon nanotube). In the conductive layer of the flexible conductor structure, the number of nanocarbon materials (carbon nanotubes) oriented parallel to the surface (one surface) of the base material is equal to the number of nanocarbon materials (carbon nanotubes) oriented vertically to the surface of the base material ( More than the number of carbon nanotubes).

  The detailed contents for the substrate can be the same as those described for the first resin layer. The contents related to the rolled conductive metal and carbon nanotube, the contents related to the bent portion of the conductive layer, and the contents related to the additional resin layer (eg, second resin layer) are also described in the above wiring board. Applied.

  The conductive layer is preferably patterned to have an open space (open space). The ratio of the open space to the total area of the conductive layer is preferably 50% or more, more preferably 80% or more, still more preferably 90% or more, even more preferably 95% or more, and most preferably Is 99% or more.

  When the conductor structure is bent 40,000 times with a bending rate radius (bending radius) of 1 mm, the resistance change rate defined above is preferably 400% or less. Since the resistance change rate has been described above, it will be omitted.

  The conductor structure may be a flexible substrate, a transparent electrode, or a lead wire.

  Specific examples are presented below. However, the examples described below are merely for specifically illustrating and explaining the above-described embodiments, and the scope of the present specification is not limited thereby.

Reference example: Production of plating bath [1] Production of plating bath 1:
In a reaction vessel containing water, add 140 g / L potassium cyanide, 40 g / L silver cyanide, 15 g / L potassium carbonate, 4 ml / L brightener (AgO-56, manufactured by Art Technical) and completely dissolve. It was. The brightener has a silver purity of 99.10% and contains selenium.
The obtained solution was treated with 2-3 g / L activated carbon and filtered, and then 5 ml / L surfactant (Silver Glow TY, manufactured by Meltex) was added, and 10 g / L carbon nanotubes (VGCF) were added thereto. , Manufactured by Showa Denko KK) (diameter 15 nm, length 3 μm), stirred for 15 minutes, and dispersed for 15 minutes using ultrasonic waves. This process (15 minutes of stirring and ultrasonic waves) was repeated 5 times to obtain a plating bath 1.

[2] Plating bath 2 production:
A plating bath 2 was obtained in the same manner as the plating bath 1 except that the concentration of carbon nanotubes was changed to 5 g / L.

[3] Plating bath 3 production:
A plating bath 3 was obtained in the same manner as the plating bath 1 except that the concentration of carbon nanotubes was 1 g / L.

[4] Plating bath 4 production:
A plating bath 4 was obtained in the same manner as the plating bath 1 except that carbon nanotubes were not used.

Example 1:
Plating was performed using the apparatus schematically shown in FIG. FIG. 4 shows a flowchart of the manufacturing process of the flexible wiring board.

  [1] A rolled copper foil (copper foil) of 10 cm × 10 cm × 6 μm is prepared as a coating, and a plating resist (plating resist, resin type: Photec RY5319, manufactured by Hitachi Chemical Co., Ltd. (product) Name)).

In the plating bath 1, a rolled copper foil (that is, a cathode) and a counter electrode (that is, an anode) as a coating that was previously degreased for 10 minutes were placed, and the plating bath was stirred at a temperature of 20 ° C. Along with stirring, a power source was connected to the anode and the cathode, and current was applied at an average current density of 1 A / dm ² to perform electrodeposition (plating). The thickness of the obtained electrodeposit product (hereinafter referred to as silver-CNT composite) was 30 μm.

  After the completion of plating, the photoresist was removed, and the copper foil was etched away using a copper selective etching solution CS (manufactured by Nippon Chemical Industry Co., Ltd., trade name).

  The 30 μm-thick silver-CNT composite obtained above was cold-rolled several times and stretched to a thickness of 6 μm (rolling rate: 20%).

  The rolling rate is calculated as follows.

Rolling ratio (%) = [Metal thickness after rolling / Metal thickness before rolling] × 100 (%)
Here, by rolling, at least a part of the plurality of carbon nanotubes in the conductive layer is oriented in parallel to the surface of the first resin layer, and the number of carbon nanotubes oriented in parallel to the surface of the first resin layer. Was confirmed by a scanning electron microscope (SEM) to be larger than the number of carbon nanotubes oriented perpendicular to the surface of the first resin layer.

  Five polyimide films (UPILEX-25VT (trade name, manufactured by Ube Industries, Ltd.)) having a thickness of 25 μm are laminated on one surface of the rolled silver-CNT composite under heating / pressure, and a polyimide resin layer having a thickness of 125 μm is formed. A 10 cm × 10 cm structure having a 6 μm thick silver-CNT composite disposed thereon was obtained.

  Next, the silver-CNT composite was patterned by photolithography so that the ratio of line (L) / space (S) was 70 μm / 700 μm in all directions. A scanning electron microscope (SEM) image of the obtained pattern is shown in FIG. FIG. 5 is an SEM image of the flexible wiring board observed from the conductive layer side in the flexible wiring board having the first resin layer and the conductive layer obtained here.

  A polyimide coverlay film CISV1215 (made by Nikkan Kogyo Co., Ltd., trade name) having a thickness of about 25 μm is laminated on the silver-CNT composite mesh pattern by a heating and pressurizing process, and can be cut to a predetermined size. A conductive wiring board was obtained. The obtained flexible wiring board is schematically shown in FIG. FIG. 6 is a schematic diagram of the substrate observed from the second resin layer side and a schematic diagram of the substrate observed from the side surface in the obtained flexible wiring board.

  As a result of the calculation, it was found that the strain (ε) of the metal foil was 0.037.

  [2] A part of the obtained silver-CNT composite is used as a sample. The sample was put in concentrated nitric acid to completely dissolve and remove the silver matrix, and then the carbon nanotubes in the obtained solution were collected by filtration, washed with water, vacuum dried and measured for weight. As a result, it was confirmed that the carbon nanotube content in the silver-CNT composite was 0.112 wt% based on the total weight of the silver-CNT composite.

Example 2:
[1] A silver-CNT composite having a thickness of 12 μm is obtained by plating using the plating bath 1, and the same as in Example 1 except that this is rolled and stretched to a thickness of 6 μm. A wiring board was manufactured.

  [2] As a result of measurement by the same method as in Example 1, it was confirmed that the carbon nanotube content in the obtained silver-CNT composite was 0.095% by weight.

Example 3:
[1] A wiring board of Example 3 was manufactured in the same manner as Example 1 except that the plating bath 2 was used instead of the plating bath 1.

  [2] As a result of measurement by the same method as in Example 2, it was confirmed that the carbon nanotube content in the obtained silver-CNT composite was 0.063 wt%.

Example 4:
[1] A wiring board of Example 4 was produced in the same manner as in Example 1 except that a silver-CNT composite having a thickness of 6 μm was obtained by plating using the plating bath 1 and rolling was omitted.

  [2] As a result of measurement by the same method as in Example 1, it was confirmed that the content of carbon nanotubes in the obtained silver-CNT composite was 0.063 wt%.

Example 5:
[1] A wiring board of Example 5 was manufactured in the same manner as Example 1 except that the plating bath 3 was used instead of the plating bath 1.

  [2] As a result of measurement by the same method as in Example 1, it was confirmed that the content of carbon nanotubes in the obtained silver-CNT composite was 0.011% by weight.

Comparative Example 1:
A wiring board of Comparative Example 1 was manufactured in the same manner as Example 1 except that the plating bath 4 (containing no CNT) was used instead of the plating bath 1. Here, in the flexible wiring board having the first resin layer and the conductive layer before forming the second resin layer of Comparative Example 1, the scanning electron microscope of the flexible wiring board observed from the conductive layer side An (SEM) image is shown in FIG.

Comparative Example 2:
A wiring board was produced in the same manner as in Example 1 except that 6 μm rolled copper (HA-V2 foil JX Nippon Mining & Metals Co., Ltd .; trade name) was used as the conductive layer without performing the plating step.

Comparative Example 3:
A commercially available 30 μm thick aluminum foil is rolled to prepare a 6 μm rolled aluminum foil. A wiring board was manufactured in the same manner as in Example 1 except that a rolled aluminum foil was used without performing the plating step.

Experimental Example 1: Surface Resistance Measurement Surface resistance was measured for the wiring boards of Examples 1 to 5 and Comparative Example 1 by using the MCP-T610 (manufactured by MITSUBISHI Chemical Analytech, manufactured by MITSUBISHI Chemical Analytech) by the 4-terminal probe method. The results are shown in Table 1 below.

  From the results in Table 1, it was confirmed that the addition of carbon nanotubes did not substantially change the surface resistance of the sample (that is, negative influence on conductivity).

Experimental Example 2: Flexibility test by measuring resistance change rate For the wiring boards of Examples 1 to 5 and Comparative Examples 1 to 3, the resistance change rate was measured by the following method, and the results are shown in Table 2 and FIG. Examples 1 to 5 and Comparative Example 1), FIG. 9 (Comparative Example 2), and FIG. 10 (Comparative Example 3) are shown.

Before bending, the resistance (R ₀ ) having a width of 20 mm and a length of 90 mm is measured from the end (edge) of the exposed substrate. Next, the central portion of the wiring board (that is, a position 50 mm from the end (edge)) is bent at a curvature radius (that is, a bending radius or a bending radius) of 1 mm (so that the wiring side is on the outside) 180 degrees (fold) ) For the continuous bending test, CFT-200R (Flexible tester series manufactured by Covotech) was used. The method shown in FIG. 8 is repeated up to 75,000 cycles at a speed of 1 cycle / 2 seconds. A resistance (R) having a width of 20 mm and a length of 90 mm from the end of the substrate exposed in a predetermined cycle is measured using a resistance measuring device 34401A Multimeter (manufactured by Hewlett Packard), and the resistance change rate is obtained by the following equation. It was.

[(R ₀ −R) / R ₀ ] × 100 = resistance change rate

  From the results of Table 2 and FIG. 9, the following is considered.

  The wiring board of Comparative Example 1 does not contain carbon nanotubes and uses silver wiring. Examples 1 to 5 are silver wirings containing carbon nanotubes. After the bending cycle, it was confirmed that the wiring boards of Examples 1 to 5 had a smaller resistance change rate than the wiring board of Comparative Example 1. In other words, it was confirmed that the bending resistance was improved by adding carbon nanotubes.

  In Example 5, the content of carbon nanotubes is the smallest of the Examples, and the rate of change in resistance is smaller than Comparative Example 1, but larger than the other Examples. From this, it can be said that the content of carbon nanotubes of 0.01% by weight or more is preferable. From the results of Examples 1 to 3, it was confirmed that the bending resistance increases when the content of carbon nanotubes increases.

  The wiring boards of Example 3 and Example 4 have the same carbon nanotube content, but have different rolling rates of 20% and 100%, respectively. It was confirmed that the increase in resistance change rate can be remarkably reduced by rolling. Without being bound by any particular theory, this is thought to be due to the increase in the number of carbon nanotubes horizontally aligned on the substrate while rolling improves the dispersibility of the carbon nanotubes in the metal foil. . It was confirmed by SEM that the carbon nanotubes were oriented in the horizontal direction as the rolling rate became 100% (no rolling), 50% (2 times compression), and 20% (5 times compression).

  FIG. 10 is a graph showing the resistance change rate of the specimen after the flexibility test of the rolled copper wiring board of Comparative Example 2, and FIG. This is a graph of the resistance change rate of the specimen.

  It was confirmed that the rolled copper wiring board of Comparative Example 2 and the rolled aluminum wiring board of Comparative Example 3 exhibited very poor bending resistance. In other words, it can be said that the silver wiring has improved bending resistance compared to the copper wiring or the aluminum wiring. Silver wiring has a characteristic of being easily sulfided in the air, has a problem of ion migration, and its application as a wiring has been limited. However, it was confirmed that the wiring board of the example can exhibit improved bending resistance while solving all of these problems related to wiring.

  This experiment was conducted in a system in which the metal thickness was constant with the flexible wiring board (FPC) in mind. However, there is a large correlation between metal thickness and bending resistance. The JX metal website (http://www.nmm.jx-group.co.jp/products/rolled_copper_foil/ha.html) as of January 28, 2016, which serves as a reference material, shows the metal thickness and bending resistance. The bending resistance increases as the thickness decreases. In this regard, as a result of performing a reliability test using a rolled copper foil, it was found that when the thickness of the copper foil is 2/3, the life of the bending test having a life of 10% increase in resistance is doubled. . This result is close to that of the JX Metals website.

  Therefore, the life of the bendability test conducted using 6 μm Ag-CNT was 6200 times (the life was calculated by linear approximation from the results of 5000 times and 10,000 times), and the thickness and bending of Ag-CNT calculated by simulation were calculated. FIG. 12 shows the relationship with the life of the property test. It has been found that the lifetime can be extended by reducing the thickness of the Ag-CNT.

  Although the embodiments have been described in detail above, the scope of rights of the present specification is not limited thereto, and modifications and improvements of those skilled in the art using the concepts defined in the following claims are also covered by the rights. Belonging to within range.

100 flexible wiring board,
10 first resin layer,
20 conductive layer,
30 Second resin layer.

Claims (28)

A first resin layer;
A flexible wiring board having a conductive layer disposed on one surface of the first resin layer,
The conductive layer includes a conductive metal and a nanocarbon material dispersed in the conductive metal;
A flexible wiring board that is used with a bent portion in at least one portion of the conductive layer.   The flexible wiring board according to claim 1, wherein the nanocarbon material includes carbon nanotubes, fullerene, graphene, or a combination thereof.   The flexible wiring board according to claim 1, wherein the nanocarbon material includes a plurality of carbon nanotubes.   The flexible wiring board according to claim 1, further comprising a second resin layer on the conductive layer.   The flexible wiring board according to claim 4, wherein the first resin layer and the second resin layer have insulating properties.   The first resin layer and the second resin layer are polyester resin, polyacrylic resin, polyolefin resin, cellulose resin, polycarbonate resin, polyimide resin, polyamide resin, polyphenylene sulfide, polyether ether ketone. The flexible wiring board according to claim 4, comprising a liquid crystal polymer, an epoxy resin, or a combination thereof.   The conductive metal may be silver (Ag), copper (Cu), nickel (Ni), gold (Au), aluminum (Al), tungsten (W), platinum (Pt), iron (Fe), or a combination thereof. The flexible wiring board of any one of Claims 1-6 containing.   The flexible wiring board according to claim 7, wherein the conductive metal includes silver (Ag).   The flexible wiring board according to any one of claims 2 to 8, wherein the conductive layer is a rolled product of a eutectoid composite by electrodeposition of the conductive metal and the carbon nanotube.   The flexible product according to claim 9, wherein the rolled product is obtained by rolling such that the eutectoid composite obtained by electrodeposition is 50% or less of the thickness obtained by electrodeposition. Wiring board.   The flexible wiring board according to any one of claims 3 to 10, wherein at least a part of the plurality of carbon nanotubes is oriented in parallel with the surface of the first resin layer.   The flexible wiring board according to claim 11, wherein the number of carbon nanotubes oriented parallel to the surface of the first resin layer is greater than the number of carbon nanotubes oriented perpendicular to the surface of the first resin layer. .   The flexible wiring board according to claim 1, wherein a content of the nanocarbon material is 0.01% by weight or more based on a total weight of the conductive layer.   The flexible wiring board according to claim 1, wherein a content of the nanocarbon material is 0.05% by weight or more and 1% by weight or less based on a total weight of the conductive layer. .   The flexible wiring board according to any one of claims 1 to 14, wherein a bending rate radius of the bent portion is 3 mm or less.   The flexible wiring board according to claim 1, wherein the bent portion is formed by sliding bending, bending bending, hinge bending, or a repetitive operation combining these.   The flexible wiring board according to any one of claims 1 to 16, wherein the resistance change rate is 400% or less when the wiring board is bent by 40,000 diffractions with a bending rate radius of 1 mm.   The flexible wiring board according to claim 1, wherein the conductive layer has a thickness of 0.2 μm to 20 μm.   The flexible wiring board according to claim 1, wherein the first resin layer has a thickness of 10 μm to 150 μm.   The electronic device containing the flexible wiring board of any one of Claims 1-19. A method for manufacturing a flexible wiring board according to any one of claims 1 to 19,
Providing a plating bath comprising a conductive metal salt compound and a nanocarbon material;
Arranging a metal plate and a counter electrode in the plating bath;
A eutectoid composite comprising a current flowing between the metal plate and the counter electrode, electrodeposition, and the conductive metal and the nanocarbon material dispersed in the conductive metal on the metal plate. Forming, and
Rolling the eutectoid composite obtained by electrodeposition so as to have a thickness of 50% or less of the thickness obtained by electrodeposition;
Disposing a first resin layer on one surface of the rolled eutectoid composite. A method for producing a flexible wiring board.   The method according to claim 21, wherein the rolling increases the number of nanocarbon materials oriented parallel to the surface of the first resin layer. A substrate;
A conductive layer disposed on one surface of the substrate; and a flexible conductor structure having:
The conductive layer includes a conductive metal and a plurality of carbon nanotubes dispersed in the conductive metal,
A flexible conductor structure that is used with a bent portion at least at a part of the conductive layer.   24. The flexible conductor structure of claim 23, wherein the number of carbon nanotubes oriented parallel to the surface of the substrate is greater than the number of carbon nanotubes oriented perpendicular to the surface of the substrate.   The flexible conductor structure according to claim 23 or 24, wherein the conductive layer includes a rolled product of a eutectoid composite by electrodeposition of the conductive metal and the carbon nanotube.   The flexible conductor structure according to any one of claims 23 to 25, wherein the conductive layer is patterned to have an open space.   27. The flexible conductor according to any one of claims 23 to 26, wherein when the flexible conductor structure is bent by 40,000 diffractions with a bending rate radius of 1 mm, the resistance change rate is 400% or less. Structure.   The flexible conductor structure according to any one of claims 23 to 27, wherein the structure is a flexible wiring board, a transparent electrode, or a lead wire.